1. Field of the Invention
The present invention relates to a development cartridge for developing a latent image formed on an image bearing member by using a developer, and to an image forming apparatus in which a plurality of development cartridges are detachably attached to a rotary.
Here, an image forming apparatus is an apparatus forming an image on a recording medium by using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (light emitting diode (LED) printer, a laser beam printer, or the like), an electrophotographic facsimile apparatus, and an electrophotographic word processor.
A recording medium is a medium on which an image is formed by an electrophotographic image forming apparatus; examples of the recording medium include a paper sheet and an Over Head Projector (OHP) sheet.
A development cartridge is a cartridge which has a developer bearing member and a developer container for developing a latent image formed on an image bearing member such as an electrophotographic photosensitive member by using a developer and which is detachably attached to a rotary rotatably provided in the apparatus main body of an electrophotographic image forming apparatus.
2. Description of the Related Art
In recent years, the demand for a color electrophotographic image forming apparatus capable of color image formation has increased, and the introduction of an inexpensive color electrophotographic image forming apparatus, more specifically, one whose price is low enough to be purchased by a general user, is expected. To realize such an inexpensive color electrophotographic image forming apparatus, a further reduction in the size of a color electrophotographic image forming apparatus is required.
In view of this, as discussed in Japanese Patent Application Laid-Open No. 2001-75328 and Japanese Patent Application Laid-Open No. 2004-125956, there has been proposed a rotary type color electrophotographic image forming apparatus equipped with a rotary allowing mounting of a plurality of development cartridges. In this color electrophotographic image forming apparatus, the rotary is rotatably provided in the apparatus main body of the electrophotographic image forming apparatus to switch each development cartridge to a development position where it is opposite to the electrophotographic photosensitive member. Further, the development cartridge has a development roller for developing a latent image formed on the electrophotographic photosensitive member by using the toner contained, and is detachably attached to the rotary.
Regarding this rotary type color electrophotographic image forming apparatus, there has been discussed a construction in which a cover in the apparatus upper surface is opened to perform the attachment and detachment of the development cartridge from above. Further, Japanese Patent Application Laid-Open No. 2001-75328 discusses a construction in which, in order to achieve an improvement in terms of the operability at the time of attachment of the development cartridge, each development cartridge is provided with an identification indicator indicating, at a position visible from above, the color of the toner contained and the direction in which the attachment to the rotary is to be effected. Further, Japanese Patent Application Laid-Open No. 2001-75328 discusses a construction in which the detachment of the development cartridge from the rotary is only possible in a state in which the identification indicator is directed upwards. More specifically, the identification indicator is provided on the surface of the development cartridge attached to the rotary directed outwards in the radial direction of the rotary.
In the above related-art example, through the rotation of the rotary, the development cartridges mounted on the rotary are successively switched to the development position where they are opposite to the electrophotographic photosensitive member, and the development roller and the electrophotographic photosensitive member are opposite to each other to effect development with the toner of each color. More specifically, the development roller is arranged on the surface of the development cartridge where the identification indicator is provided, for example, on the surface directed outwards in the radial direction of the rotary. Further, generally speaking, in a development cartridge, on the surface where the development roller is arranged, there are arranged, not only the development roller, but also a layer thickness regulating member regulating the thickness of the toner layer on the development roller, a scattering prevention member preventing scattering of toner, a grip portion for replacing the cartridge, etc. Thus, to achieve a further reduction in size while maintaining the improved operability at the time of replacement of the development cartridge, it is rather difficult to provide the identification indicator on the surface where the development roller is arranged.